An fMRI study of self-reflection about body image: Sex differences

Recent functional imaging studies suggest key involvement of medial prefrontal cortex (mPFC) in processes of self-evaluation. Additional behavioral evidence suggests significant sex differences in sensitivity both to social norms and to information about one’s own body, particularly as it pertains to assessments of self-worth. Because these observed sex differences are hypothesized to arise from differences in cognitive representations of the self, brain activation differences in mPFC might likewise be expected while men and women process information about body image. In this study, 10 females and nine males viewed images of gender-matched bodies of either an overweight body type or a thin body type while undergoing functional MRI (fMRI) scanning. While viewing these images, participants were instructed to make evaluations of their own bodies in relation to the images displayed. Significant within-group contrasts in mPFC activation were observed for women only, with relatively higher activation for overweight images versus thin images. Men showed no significant mPFC activation while processing either type of image. These results are consistent with cognitive models of self-representation, particularly those developed within social and cultural theoretical frameworks, where body size is hypothesized to play a dominant role in schematic representations of self-worth for many women.